Slide rail assembly, sheet feeder, and image forming apparatus

ABSTRACT

A slide rail assembly includes an inner rail unit, a pair of first and second outer rails, first and second roller mounted to the inner rail unit, and third and fourth rollers mounted to the pair of first and second outer rails. The inner rail unit includes an inner substrate assembly, a pair of first bent portions provided to a first side of the inner substrate assembly, and a pair of second bent portions provided to a second side of the inner substrate assembly. The first outer rail includes a first outer substrate and a pair of third bent portions. The second outer rail includes a second outer substrate and a pair of fourth bent portions. The pair of first and second outer rails is disposed with the pairs of third and fourth bent portions facing inward, and slidable against the inner rail unit.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is based on and claims priority pursuant to 35U.S.C. §119 to Japanese Patent Application No. 2012-137448, filed onJun. 19, 2012, in the Japan Patent Office, the entire disclosure ofwhich is hereby incorporated by reference herein.

BACKGROUND

1. Technical Field

Exemplary aspects of the present invention generally relate to a sliderail assembly for use in a cabinet or a drawer, tray, or the likeslidably attachable to an image forming apparatus such as a copier,printer, and a facsimile machine; a sheet feeder including the sliderail assembly; and an image forming apparatus including the sheetfeeder.

2. Related Art

As illustrated in FIG. 1, one example of a related-art slide railassembly 101 is constructed of an outer rail 110, an inner rail 120assembled with the outer rail 110 to be slidably accommodatable withinthe outer rail 110, an increased diameter roller 103 provided to adownstream end of the inner rail 120 in a direction of accommodation ofthe inner rail 120 within the outer rail 110 (hereinafter referred to asan accommodation end) to engage between inwardly facing upper and loweredges 111 of the outer rail 110, and a pair of reduced diameter rollers104 (one of which is shown in FIG. 1) provided to a downstream end ofthe outer rail 110 in a direction of withdrawal of the inner rail 120from the outer rail 110 (hereinafter referred to as withdrawal end) tosandwich inwardly facing upper and lower edges 121 of the inner rail120. A pin shaft 122 is inserted into the increased diameter roller 103and a pin hole 120 a formed in the inner rail 120 so that the increaseddiameter roller 103 is mounted to the inner rail 120. Similarly, a pinshaft 112 is inserted into each reduced diameter roller 104 and each pinhole 110 a formed in the outer rail 110 so that the pair of reduceddiameter rollers 104 is mounted to the outer rail 110, respectively.

FIGS. 2A and 2B are schematic views of the related-art slide railassembly 101, differing in a total length thereof, respectively.Specifically, the total length of the slide rail assembly 101illustrated in FIG. 2B is longer than the total length of the slide railassembly 101 illustrated in FIG. 2A. It is to be noted that, for ease ofillustration, only one of the reduced diameter rollers 104 is shown inFIGS. 2A and 2B.

As described previously, the related-art slide rail assembly 101 isconstructed of two separate rails, that is, the outer rail 110 and theinner rail 120. The inner rail 120 is slidable against the outer rail110 by a distance identical to total length L1 or L2 of the outer rail110 illustrated in FIG. 2A or 2B. In other words, the longer theslidable distance of the inner rail 120 against the outer rail 110, thelonger the total length L1 or L2 of the outer rail 110, whichcorresponds to the total length of the slide rail assembly 101 in astate in which the inner rail 120 is accommodated within the outer rail110. In addition, the longer the slidable distance of the inner rail 120against the outer rail 110, the longer the distance t1 or t2 between thereduced diameter roller 104 of the outer rail 110, which is a fulcrum ofslide movement of the slide rail assembly 101, and an upstream end ofthe inner rail 120 in the direction of withdrawal of the inner rail 120,that is, the accommodation end of the inner rail 120 to which theincreased diameter roller 103 is mounted. Consequently, when the innerrail 120 is withdrawn from the outer rail 110, a load applied to theupstream end of the inner rail 120 increases, thereby possibly breakingthe inner rail 120. Thus, insufficient load-bearing capacity of theinner rail 120 limits any increase in the slidable distance of the innerrail 120 against the outer rail 110.

To solve the above-described problem of limited load-bearing capacity,another example of a related-art slide rail assembly 201 is constructedof three separate, telescoping rails as illustrated in FIG. 3. The sliderail assembly 201 includes an outer rail 210, an intermediate rail 220slidably insertable into the outer rail 210, and an inner rail 230slidably insertable into the intermediate rail 220. The inner rail 230carries a drawer, not shown for ease of illustration.

Because the telescopic slide rail assembly 201 is constructed of thethree separate rails, a length of each rail can be reduced compared tothe slide rail assembly 101, which is constructed of the two separaterails, thereby downsizing the total length of the slide rail assembly201 in an accommodation state in which both the intermediate rail 220and the inner rail 230 are accommodated within the outer rail 210. Inaddition, the shorter length of each rail improves load durability.

However, because the intermediate rail 220, into which the inner rail230 is inserted, is further inserted into the outer rail 210 in theaccommodation state, a height of the slide rail assembly 201 isincreased compared to the slide rail assembly 101 constructed of the tworails.

SUMMARY

In view of the foregoing, illustrative embodiments of the presentinvention provide a compact slide rail assembly with improved strength,a novel sheet feeder including the slide rail assembly, and a novelimage forming apparatus including the sheet feeder.

In one illustrative embodiment, a slide rail assembly includes an innerrail unit, a pair of first and second outer rails to sandwich the innerrail unit, and first, second, third, and fourth rollers. The inner railunit includes a rectangular inner substrate assembly, a pair of firstbent portions provided to a first side of the inner substrate assemblyin thickness directions, one end of which is continuous with both edgesof the inner substrate assembly in width directions, and opposite endsof which are bent toward each other, and a pair of second bent portionsprovided to a second side of the inner substrate assembly opposite thefirst side in the thickness directions, one end of which is continuouswith both edges of the inner substrate assembly in the width directions,and opposite ends of which are bent toward each other. The first outerrail includes a rectangular first outer substrate, and a pair of thirdbent portions, one end of which is continuous with both edges of thefirst outer substrate in width directions, and opposite ends of whichare bent toward each other. The second outer rail includes a rectangularsecond outer substrate, and a pair of fourth bent portions, one end ofwhich is continuous with both edges of the second outer substrate in thewidth directions, and opposite ends of which are bent toward each other.The pair of first and second outer rails is disposed with the pairs ofthird and fourth bent portions facing inward, and slidable against theinner rail unit in both a withdrawal direction and an accommodationdirection along longitudinal directions of the inner substrate assembly.The first roller is mounted to a leading end of the inner rail unit inthe withdrawal direction to slidably contact inner surfaces of the pairof third bent portions. The second roller is mounted to a leading end ofthe inner rail unit in the accommodation direction to slidably contactinner surfaces of the pair of fourth bent portions. The third roller ismounted to a leading end of the first outer rail in the accommodationdirection to slidably contact inner surfaces of the pair of first bentportions. The fourth roller is mounted to a leading end of the secondouter rail in the withdrawal direction to slidably contact innersurfaces of the pair of second bent portions.

In another illustrative embodiment, a sheet feeder includes a sheet traywithdrawable from the sheet feeder to accommodate sheets, and the sliderail assembly described above mounted to both lateral sides of the sheettray to guide the sheet tray in a withdrawal direction.

In yet another illustrative embodiment, an image forming apparatusincludes the sheet feeder described above and the slide rail assemblydescribed above.

Additional features and advantages of the present disclosure will becomemore fully apparent from the following detailed description ofillustrative embodiments, the accompanying drawings, and the associatedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be more readily obtained as the same becomesbetter understood by reference to the following detailed description ofillustrative embodiments when considered in connection with theaccompanying drawings, wherein:

FIG. 1 is an exploded perspective view illustrating an example of aconfiguration of a related-art slide rail assembly;

FIGS. 2A and 2B are schematic views of the related-art slide railassembly, differing in a total length thereof, respectively;

FIG. 3 is a perspective view illustrating another example of aconfiguration of a related-art slide rail assembly;

FIG. 4 is a vertical cross-sectional view illustrating an example of aconfiguration of an image forming apparatus according to illustrativeembodiments;

FIG. 5 is a perspective view illustrating an example of a configurationof a slide rail assembly according to a first illustrative embodiment;

FIG. 6 is an exploded perspective view of the slide rail assemblyillustrated in FIG. 5;

FIG. 7 is an exploded vertical cross-sectional view of the slide railassembly;

FIG. 8 is an exploded perspective view of the slide rail assembly;

FIG. 9 is a partial exploded perspective view illustrating mounting of athird roller to a first outer rail;

FIG. 10 is a vertical cross-sectional view of the slide rail assemblyaccording to the first illustrative embodiment;

FIG. 11A is a perspective view illustrating a first inner rail and afirst outer rail of a slide rail assembly according to a secondillustrative embodiment;

FIG. 11B is a perspective view illustrating a second inner rail and asecond outer rail of the slide rail assembly according to the secondillustrative embodiment, and

FIG. 12 is a vertical cross-sectional view illustrating an example of aconfiguration of a slide rail assembly according to a variation ofillustrative embodiments.

DETAILED DESCRIPTION

In describing illustrative embodiments illustrated in the drawings,specific terminology is employed for the sake of clarity. However, thedisclosure of this patent specification is not intended to be limited tothe specific terminology so selected, and it is to be understood thateach specific element includes all technical equivalents that havesubstantially the same function, operate in a similar manner, andachieve a similar result.

Illustrative embodiments of the present invention are now describedbelow with reference to the accompanying drawings. In a later-describedcomparative example, illustrative embodiment, and exemplary variation,for the sake of simplicity the same reference numerals will be given toidentical constituent elements such as parts and materials having thesame functions, and redundant descriptions thereof omitted unlessotherwise required.

A description is now given of an example of a configuration of a sliderail assembly 1 for use in an image forming apparatus 100 according to afirst illustrative embodiment.

FIG. 4 is a vertical cross-sectional view illustrating an example of aconfiguration of the image forming apparatus 100. FIG. 5 is aperspective view illustrating an example of a configuration of the sliderail assembly 1 according to the first illustrative embodiment. FIG. 6is an exploded perspective view of the slide rail assembly 1. FIG. 7 isan exploded vertical cross-sectional view of the slide rail assembly 1.

The slide rail assembly 1 is employed in the image forming apparatus 100including a body and a sheet feeder 200 withdrawably accommodatable inthe body. The sheet feeder 200 includes a sheet tray 202 thataccommodates a stack of recording media such as sheets of paper and apair of the slide rail assemblies 1 mounted to both lateral sides of thesheet tray 202, respectively. The pair of the slide rail assemblies 1guides the sheet tray 202 in a withdrawal direction in which the sheettray 202 is withdrawn from the body of the image forming apparatus 100.

The slide rail assembly 1 is constructed of an inner rail unit 10, firstand second rollers 11 and 12, both of which are rotatably mounted to theinner rail unit 10, an outer rail unit 20 including a pair of first andsecond outer rails 20A and 20B that sandwich the inner rail unit 10 onopposite sides thereof, a third roller 21 rotatably mounted to the firstouter rail 20A, and a fourth roller 22 (shown in FIG. 7) rotatablymounted to the second outer rail 20B. Both the first and second outerrails 20A and 20B are slidable against the inner rail unit 10 alonglongitudinal directions in both the withdrawal direction, in which thesheet tray 202 is withdrawn from the body of the image forming apparatus100, and an accommodation direction, in which the sheet tray 202 isaccommodated within the body of the image forming apparatus 100.Relative positions of the inner rail unit 10 and each of the first andsecond outer rails 20A and 20B are variable by sliding the first orsecond outer rail 20A or 20B against the inner rail unit 10. In otherwords, the first and second outer rails 20A and 20B are individually andindependently slidable against the inner rail unit 10 without moving inconjunction with each other.

The inner rail unit 10 is constructed of two separate rails, that is, afirst inner rail 10A and a second inner rail 10B, both of which arefixed together. It is to be noted that the first and second inner rails10A and 10B have the same basic shape and structure. Two sheets of metallaminated one atop the other are blanked and bent to form the first orsecond inner rail 10A or 10B. Thus, the same mold may be used for boththe first and second inner rails 10A and 10B.

The inner rail unit 10 has a first through-hole, that is, a firstmounting hole 10 a, to which the first roller 11 is mounted, and asecond through-hole, that is, a second mounting hole 10 b (shown in FIG.8), to which the second roller 12 is mounted. The first mounting hole 10a is provided to a downstream end of the inner rail unit 10 in thewithdrawal direction of the sheet tray 202 (hereinafter referred to as awithdrawal end), and the second mounting hole 10 b is provided to adownstream end of the inner rail unit 10 in the accommodation directionof the sheet tray 202 (hereinafter referred to as an accommodation end),which is opposite the withdrawal end. Both the first and second mountingholes 10 a and 10 b penetrate into a first inner substrate 13 providedto the first inner rail 10A and a second inner substrate 15 provided tothe second inner rail 10B.

The first inner rail 10A is constructed of the rectangular first innersubstrate 13 and a pair of first bent portions 14 that is continuouswith longitudinal edges of the first substrate 13, respectively, withopposed ends thereof that are bent inward toward each other andgenerally parallel to the first substrate 13.

It is to be noted that double-headed arrow Y in the drawings indicatesdirections in which the inner rail unit 10 and the pair of first andsecond outer rails 20A and 20B are slidable (hereinafter referred to asslide directions), which correspond to the longitudinal directions ofthe first and second substrates 13 and 15 and third and fourthsubstrates 23 and 25 described later. Double-headed arrow X indicatesdirections of a height of each of the inner rail unit 10 and the pair offirst and second outer rails 20A and 20B, which correspond to the widthdirections of each of the first, second, third, and fourth substrates13, 15, 23, and 25. Double-headed arrow Z indicates directions of athickness of each of the inner rail unit 10, the pair of first andsecond outer rails 20A and 20B, the first, second, third, and fourthsubstrates 13, 15, 23, and 25.

A length of the first substrate 13 is longer than a length of each firstbent portion 14 in the longitudinal directions. Specifically, asillustrated in FIG. 6, in place of the pair of first bent portions 14, afirst extending portion 13A is provided to the withdrawal end of thefirst substrate 13. The first extending portion 13A is a part of thefirst substrate 13, and the first mounting hole 10 a is formed at thecenter thereof in the height directions. In addition, as describedpreviously, the second mounting hole 10 b is formed at the center of theaccommodation end of the first substrate 13 in the height directions. Toreinforce the first inner rail 10A, a first bulge 13B that slightlybulges outward in the thickness directions of the first substrate 13 isprovided at the center of the first substrate 13 across the longitudinaldirections, excluding a part in which the first extending portion 13A isprovided. Specifically, excluding the part in which the first extendingportion 13A is provided, the first bulge 13B is provided to the firstsubstrate 13 across the longitudinal directions at a position away fromboth upper and lower edges of the first substrate 13.

Each first bent portion 14 is L-shaped in cross-section and isconstructed of a first standing plate 14A, which is bent in a directionperpendicular to the first substrate 13, and a first parallel plate 14B,which is bent in a direction perpendicular to the first standing plate14A to be parallel to the first substrate 13. The pair of first bentportions 14 is formed on one side of the first substrate 13 in thethickness directions, respectively.

Similarly, the second inner rail 10B is constructed of the rectangularsecond inner substrate 15 and a pair of second bent portions 16 that iscontinuous with longitudinal edges of the second substrate 15,respectively, with opposed ends thereof that are bent inward toward eachother and generally parallel to the second substrate 15. The first andsecond inner substrates 13 and 15 together form an inner substrateassembly 135 of the inner rail unit 10.

A length of the second substrate 15 is longer than a length of eachsecond bent portion 16 in the longitudinal directions. Specifically, asillustrated in FIGS. 6 and 8, in place of the pair of second bentportions 16, a second extending portion 15A is provided to theaccommodation end of the second substrate 15. The second extendingportion 15A is a part of the second substrate 15, and the secondmounting hole 10 b is formed at the center thereof in the heightdirections. In addition, as described previously, the first mountinghole 10 a is provided at the center of the withdrawal end of the secondsubstrate 15 in the height directions. To reinforce the second innerrail 10B, a second bulge 15B that slightly bulges outward in thethickness directions of the second substrate 15 is provided at thecenter of the second substrate 15 across the longitudinal directions,excluding a part in which the second extending portion 15A is provided.Specifically, excluding the part in which the second extending portion15A is provided, the second bulge 15B is provided to the secondsubstrate 15 across the longitudinal directions at a position away fromboth upper and lower edges of the second substrate 15.

Each second bent portion 16 is L-shaped in cross-section and isconstructed of a second standing plate 16A, which is bent in a directionperpendicular to the second substrate 15, and a second parallel plate16B, which is bent in a direction perpendicular to the second standingplate 16A to be parallel to the second substrate 15. The pair of secondbent portions 16 is formed on the other side of the second substrate 15,respectively, in the thickness directions opposite the side in which thepair of first bent portions 14 is formed in the first substrate 13 ofthe first inner rail 10A.

The first and second substrates 13 and 15 of the first and second innerrails 10A and 10B are fixed together back-to-back by welding, bonding,or any well-known method to form the inner rail unit 10 with the pairsof first and second bent portions 14 and 16 protruding outward inopposite directions, respectively. As a result, the first and secondmounting holes 10 a and 10 b are formed in the inner rail unit 10 at thewithdrawal and accommodation ends, respectively.

As shown in FIG. 7, the first roller 11 is constructed of a disk-shapedfirst main body 2A, a pedestal 3 tapered toward a leading end andcontinuous coaxially with the main body 2A, a first hole 11 apenetrating the axial center of both the main body 2A and the pedestal3, and a shaft 4A inserted into the first hole 11 a. A diameter of themain body 2A increases approaching the center thereof in the thicknessdirections. A maximum diameter D2 of the main body 2A is slightlysmaller than a height C20 between third standing plates 24A of a pair ofthird bent portions 24 provided to the first outer rail 20A, which aredescribed in detail later. A thickness T2 of the main body 2A isslightly smaller than a width T20 between the third substrate 23 of thefirst outer rail 20A and third parallel plates 24B of the pair of thirdbent portions 24, which are also described in detail later. Thus, thefirst roller 11 having the main body 2A slidably engages inner surfacesof the pair of third bent portions 24 of the first outer rail 20A.

The shaft 4A is constructed of a main body 41, a reduced diameterportion 42 continuous with one end of the main body 41, and an increaseddiameter portion 43 continuous with the opposite end of the main body41. A diameter D42 of the reduced diameter portion 42 is smaller than adiameter of the main body 41, and a diameter of the increased diameterportion 43 is larger than the diameter of the main body 41. The mainbody 41, the reduced diameter portion 42, and the increased diameterportion 43 are coaxial. An axial length T41 of the shaft 4A, that is, atotal thickness of the main body 41 and the increased diameter portion43, is slightly longer than a total thickness T11 of the main body 2Aand the pedestal 3 of the first roller 11. When the first roller 11 ismounted to the first inner rail 10A, an end face of the main body 41 ofthe shaft 4A contacts the first substrate 13 of the first inner rail10A. The diameter D42 of the reduced diameter portion 42 is slightlysmaller than a diameter of the first mounting hole 10 a, and an axiallength T42 of the reduced diameter portion 42 is slightly longer than atotal thickness of the first and second substrates 13 and 15 laminatedtogether.

The first roller 11 on the pedestal 3 side is positioned closer to oneface of the first substrate 13 in the thickness directions so that thefirst hole 11 a formed in the first roller 11 communicates with thefirst mounting hole 10 a. The shaft 4A of the first roller 11 isinserted into the first hole 11 a and the first mounting hole 10 acommunicating with each other, and the leading end of the shaft 4A isfixed to the first substrate 13 on the opposite face of the firstsubstrate 13 using a well-known method. Thus, the first roller 11 isrotatably mounted to the first inner rail 10A. In a manner similar tothe first roller 11, the second roller 12 is rotatably mounted to thesecond inner rail 10B as described in detail below.

It is to be noted that, the first and second rollers 11 and 12 have thesame basic shape and structure, and the same reference numerals arepartially used for those components of the second roller 12 identical tothe components of the first roller 11. The second roller 12 isconstructed of a disk-shaped second main body 2B, a pedestal 3 that istapered toward a leading end and continuous coaxially with the main body2B, a second hole 12 a penetrating in the center of both the main body2B and the pedestal 3, and a shaft 4B inserted into the second hole 12a. A diameter of the main body 2B increases approaching the centerthereof in the thickness directions. A maximum diameter D2 of the mainbody 2B is slightly smaller than a height C20 between fourth standingplates 26A of a pair of fourth bent portions 26 provided to the secondouter rail 20B, which are described in detail later, and a thickness T2of the main body 2B is slightly smaller than a width T20 between thefourth substrate 25 of the second outer rail 20B and fourth parallelplates 26B of the pair of fourth bent portions 26, which are alsodescribed in detail later. Thus, the second roller 12 having the mainbody 2B slidably engages inner surfaces of the pair of fourth bentportions 26 of the second outer rail 20B.

Similarly, the first and second shaft 4A and 4B of the first and secondrollers 11 and 12 have the same basic shape and structure. The shaft 4Bis constructed of a main body 41, a reduced diameter portion 42continuous with one end of the main body 41, and an increased diameterportion 43 continuous with the opposite end of the main body 41. Adiameter D42 of the reduced diameter portion 42 is smaller than adiameter of the main body 41, and a diameter of the increased diameterportion 43 is larger than the diameter of the main body 41. The mainbody 41, the reduced diameter portion 42, and the increased diameterportion 43 are coaxial. An axial length T41 of the shaft 4B, that is, atotal thickness of the main body 41 and the increased diameter portion43, is slightly longer than a total thickness T11 of the main body 2Band the pedestal 3 of the second roller 12. When the second roller 12 ismounted to the second inner rail 10B, an end face of the main body 41 ofthe shaft 4B contacts the second substrate 15 of the second inner rail10B. The diameter D42 of the reduced diameter portion 42 is slightlysmaller than a diameter of the second mounting hole 10 b, and an axiallength T42 of the reduced diameter portion 42 is slightly longer than atotal thickness of the first and second substrates 13 and 15 laminatedtogether.

As described previously, the outer rail unit 20 is constructed of twoseparate rails, that is, the first outer rail 20A and the second outerrail 20B. It is to be noted that the first and second outer rails 20Aand 20B have the same basic shape and structure. Two sheets of metallaminated one atop the other are blanked and bent to form the first orsecond outer rails 20A or 20B. Thus, the same mold may be used for boththe first and second outer rails 20A and 20B.

The first outer rail 20A is constructed of the rectangular third outersubstrate 23 and the pair of third bent portions 24. One end of thethird bent portions 24 is continuous with longitudinal edges of thethird substrate 23, and opposite ends thereof are bent inward towardeach other. A length of the third substrate 23 is longer than the lengthof the first substrate 13 in the longitudinal directions. The pair ofthird bent portions 24 is provided to the third substrate 23 across thelongitudinal directions.

As illustrated in FIG. 8, a third mounting hole 20 a, to which the thirdroller 21 is mounted, is provided to a downstream end of the thirdsubstrate 23 in the accommodation direction of the sheet tray 202(hereinafter referred to as an accommodation end). Specifically, thethird mounting hole 20 a is formed at the center of the accommodationend of the third substrate 23 in the height directions and penetratesthe third substrate 23. To reinforce the first outer rail 20A, a thirdbulge 23A that bulges outward in the thickness directions of the thirdsubstrate 23 is provided at the center of the third substrate 23 acrossthe longitudinal directions, excluding a part in which the thirdmounting hole 20 a is formed. Specifically, excluding the part in whichthe third mounting hole 20 a is formed, the third bulge 23A is providedto the third substrate 23 across the longitudinal directions at aposition away from both upper and lower edges and both ends of the thirdsubstrate 23.

Each third bent portion 24 is L-shaped in cross-section and isconstructed of the third standing plate 24A, which is bent in adirection perpendicular to the third substrate 23, and the thirdparallel plate 24B, which is bent in a direction perpendicular to thethird standing plate 24A to be parallel to the third substrate 23. Thepair of third bent portions 24 is formed on the other side of the thirdsubstrate 23 in the thickness directions, respectively.

The second outer rail 20B is constructed of the rectangular fourth outersubstrate 25 and the pair of fourth bent portions 26. One end of thefourth bent portions 26 is continuous with longitudinal edges of thefourth substrate 25, and opposite ends thereof are bent inward towardeach other. A length of the fourth substrate 25 is longer than thelength of the second substrate 15 in the longitudinal directions. Thepair of fourth bent portions 26 is provided to the fourth substrate 25across the longitudinal directions.

As illustrated in FIGS. 6 and 8, a fourth mounting hole 20 b, to whichthe fourth roller 22 is mounted, is provided to a downstream end of thefourth substrate 4 in the withdrawal direction of the sheet tray 202(hereinafter referred to as a withdrawal end). Specifically, the fourthmounting hole 20 b is formed at the center of the withdrawal end of thefourth substrate 25 in the height directions and penetrates the fourthsubstrate 25. To reinforce the second outer rail 20B, a fourth bulge 25Athat bulges outward in the thickness directions of the fourth substrate25 is provided at the center of the fourth substrate 25 across thelongitudinal directions, excluding a part in which the fourth mountinghole 20 b is formed. Specifically, excluding the part in which thefourth mounting hole 20 b is formed, the fourth bulge 25A is provided tothe fourth substrate 25 across the longitudinal directions at a positionaway from both upper and lower edges and both ends of the fourthsubstrate 25.

Each fourth bent portion 26 is L-shaped in cross-section and isconstructed of the fourth standing plate 26A, which is bent in adirection perpendicular to the fourth substrate 25, and the fourthparallel plate 26B, which is bent in a direction perpendicular to thefourth standing plate 26A to be parallel to the fourth substrate 25. Thepair of fourth bent portions 26 is formed on one side of the fourthsubstrate 25, respectively, in the thickness directions opposite theother side in which the pair of third bent portions 24 is formed in thethird substrate 23 of the first outer rail 20A.

The third roller 21 is constructed of a disk-shaped third main body 5, apedestal 6 that is tapered toward a leading end and continuous coaxiallywith the main body 5, a hole 5 a penetrating in the center of both themain body 5 and the pedestal 6, and a shaft 7 inserted into the hole 5a. The main body 5 of the third roller 21 is cylindrically shaped andhas the same outer diameter across the thickness directions. A maximumdiameter D5 of the main body 5 is slightly smaller than a height C10between the first standing plates 14A of the pair of first bent portions14 provided to the first inner rail 10A, and a thickness T5 of the mainbody 5 is slightly shorter than a width T14 between the first substrate13 of the first inner rail 10A and the first parallel plates 14B of thepair of first bent portions 14. Thus, the third roller 21 having themain body 5 slidably engages inner surfaces of the pair of first bentportions 14 of the first inner rail 10A.

The shaft 7 is constructed of a main body 71, a reduced diameter portion72 continuous with one end of the main body 71, and an increaseddiameter portion 73 continuous with the opposite end of the main body71. A diameter D72 of the reduced diameter portion 72 is smaller than adiameter of the main body 71, and a diameter of the increased diameterportion 73 is larger than the diameter of the main body 71. The mainbody 71, the reduced diameter portion 72, and the increased diameterportion 73 are coaxial. An axial length T71 of the shaft 7, that is, atotal thickness of the main body 71 and the increased diameter portion73, is slightly longer than a total thickness T21 of the main body 5 andthe pedestal 6 of the third roller 21. When the third roller 21 ismounted to the first outer rail 20A, an end face of the main body 71 ofthe shaft 7 contacts the third substrate 23 of the first outer rail 20A.The diameter D72 of the reduced diameter portion 72 is slightly smallerthan a diameter of the third mounting hole 20 a, and an axial length T72of the reduced diameter portion 72 is slightly longer than the thicknessof the third substrate 23.

FIG. 9 is a partial exploded perspective view illustrating mounting ofthe third roller 21 to the first outer rail 20A. To mount the thirdroller 21 to the first outer rail 20A, first the third roller 21 on thepedestal 6 side is positioned closer to one face of the third substrate23 in the thickness directions so that the hole 5 a formed in the thirdroller 21 communicates with the third mounting hole 20 a. The shaft 7 ofthe third roller 21 is inserted into the hole 5 a and the third mountinghole 20 a communicating with each other, and the leading end of theshaft 7 is fixed to the third substrate 23 on the opposite face of thethird substrate 23 using a well-known method. Thus, the third roller 21is rotatably mounted to the first outer rail 20A. In a manner similar tothe third roller 21, the fourth roller 22 is rotatably mounted to thesecond outer rail 20B as described in detail below.

It is to be noted that, the third and fourth rollers 21 and 22 have thesame basic shape and structure, and the same reference numerals arepartially used for those components of the fourth roller 22 identical tothe components of the third roller 21. The fourth roller 22 isconstructed of a disk-shaped fourth main body 5, a pedestal 6 that istapered toward a leading end and continuous coaxially with the main body5, a hole 5 a penetrating in the center of both the main body 5 and thepedestal 6, and a shaft 7 inserted into the hole 5 a. The main body 5 ofthe fourth roller 22 is cylindrically shaped and has the same outerdiameter across the thickness directions. A maximum diameter D5 of themain body 5 is slightly smaller than a height C10 between the secondstanding plates 16A of the pair of second bent portions 16 provided tothe second inner rail 10B, and a thickness T5 of the main body 5 isslightly shorter than a width T14 between the second substrate 15 of thesecond inner rail 10B and the second parallel plates 16B of the pair ofsecond bent portions 16. Thus, the fourth roller 22 having the main body5 slidably engages inner surfaces of the pair of second bent portions 16of the second inner rail 10B.

A description is now given of the process of assembly of the slide railassembly 1. First, the first and second inner rails 10A and 10B areassembled into the inner rail unit 10 with the first and second rollers11 and 12 rotatably mounted as described previously. Next, the third andfourth rollers 21 and 22 are rotatably mounted to the first and secondouter rails 20A and 20B, respectively. Then, the accommodation end ofthe first inner rail 10A is positioned closer to the withdrawal end ofthe first outer rail 20A to insert the first inner rail 10A into thefirst outer rail 20A, so that the third roller 21 is positioned withinthe pair of first bent portions 14 of the first inner rail 10A and thefirst roller 11 within the pair of third bent portions 24 of the firstouter rail 20A, respectively. Thus, the first roller 11 slidably engagesthe pair of third bent portions 24, and the third roller 21 slidablyengages the pair of first bent portions 14. Thereafter, the withdrawalend of the second inner rail 10B is positioned closer to theaccommodation end of the second outer rail 20B to insert the secondinner rail 10B into the second outer rail 20B, so that the second roller12 is positioned within the pair of fourth bent portions 26 of thesecond outer rail 20B and the fourth roller 22 within the pair of secondbent portions 16 of the second inner rail 10B, respectively. Thus, thesecond roller 12 slidably engages the pair of fourth bent portions 26,and the fourth roller 22 slidably engages the pair of second bentportions 16. Accordingly, the first and second outer rails 20A and 20Bare slidable against the inner rail unit 10, respectively, to constructthe slide rail assembly 1 as illustrated in FIG. 10. FIG. 10 is avertical cross-sectional view of the slide rail assembly 1. In the sliderail assembly 1, relative positions of the inner rail unit 10 and eachof the first and second outer rails 20A and 20B are variable by slidingthe first and second outer rails 20A and 20B against the inner rail unit10, respectively.

A description is now given of functions and effects of the presentillustrative embodiment. The inner rail unit 10 has the pair of firstbent portions 14 and the pair of second bent portions 16, both of whichprotrude outward in the opposite directions, respectively. The pair offirst and second outer rails 20A and 20B has the pair of third bentportions 24 positioned opposite the pair of first bent portions 14 ofthe inner rail unit 10 and the pair of fourth bent portions 26positioned opposite the pair of second bent portions 16 of the innerrail unit 10. The pair of first bent portions 14 and the pair of thirdbent portions 24 slidably engage each other via the first and thirdrollers 11 and 21, and the pair of second bent portions 16 and the pairof fourth bent portions 26 slidably engage each other via the second andfourth rollers 12 and 22. As a result, the three separate rails, thatis, the inner rail unit 10 and the first and second outer rails 20A and20B, do not overlap one another in the vertical directions uponaccommodation of the inner rail unit 10 within both the first and secondouter rails 20A and 20B, thereby downsizing the slide rail assembly 1 inthe vertical directions compared to the related-art slide rail assembly201 in which the three separate rails are inserted into one another. Asdescribed above, the slide rail assembly 1 is constructed of threeseparate rails, that is, the inner rail unit 10 and the first and secondouter rails 20A and 20B, both of which sandwich the inner rail unit 10.The four rollers 11, 12, 21, and 22 are appropriately positioned withinthe slide rail assembly 1 so that a load applied to the withdrawal endof the slide rail assembly 1 with the fourth roller 22 as a fulcrum isspread across the inner rail unit 10 and one of the first and secondouter rails 20A and 20B, thereby improving load capacity of the sliderail assembly 1 as a whole.

The first substrate 13 and the second substrate 15 are laminated andfixed together to form the inner substrate assembly 135. The pair offirst bent portions 14 is provided to one side of the inner substrateassembly 135. One end of the first bent portions 14 is continuous withthe upper and lower longitudinal edges of the first substrate 13, andopposite ends of the first bent portions 14 are bent inward toward eachother. The pair of second bent portions 16 is provided to the other sideof the inner substrate assembly 135 opposite the one side thereof. Thus,the first and second bent portions 14 and 16 protrude outward in theopposite directions, respectively. One end of the second bent portions16 is continuous with the upper and lower longitudinal edges of thesecond substrate 15, and opposite ends of the second bent portions 16are bent inward toward each other. The inner rail unit 10 is constructedby laminating the first substrate 13 of the first inner rail 10A and thesecond substrate 15 of the second inner rail 10B together, therebyfacilitating manufacture of the slide rail assembly 1.

The first roller 11 includes the first main body 2A having the firsthole 11 a at the center therein. The first hole 11 a communicates withthe first mounting hole 10 a that penetrates both the first and secondsubstrates 13 and 15 so that the shaft 4A of the first roller 11 isinserted into both the first hole 11 a and the first mounting hole 10 ato rotatably mount the first roller 11 to the inner rail unit 10. Thesecond roller 12 includes the second main body 2B having the second hole12 a at the center therein. The second hole 12 a communicates with thesecond mounting hole 10 b that penetrates both the first and secondsubstrates 13 and 15 so that the shaft 4B of the second roller 12 isinserted into both the second hole 12 a and the second mounting hole 10b to rotatably mount the second roller 12 to the inner rail unit 10. Asa result, the first and second inner rails 10A and 10B, both of whichare laminated together, are securely fixed to each other.

The first, second, third, and fourth rollers 11, 12, 21, and 22 arerotatably provided to the slide rail assembly 1, respectively.Accordingly, the slide rail assembly 1, in which the inner rail unit 10and the first and second outer rails 20A and 20B are slidable againstone another, has improved slidability.

In the above-described example, the first and second substrates 13 and15 are laminated and fixed together back-to-back by bonding, welding, orany well-known method such that the pairs of first and second bentportions 14 and 16 protrude outward in the opposite directions,respectively. As a result, the first and second inner rails 10A and 10Bare fixed together to be assembled into the inner rail unit 10.Alternatively, the first and second inner rails 10A and 10B may be fixedtogether by inserting the shafts 4A and 4B of the first and secondrollers 11 and 12 into the first and second mounting holes 10 a and 10b, respectively, without bonding, welding, or the like.

A description is now given of a second illustrative embodiment of thepresent invention with reference to FIGS. 11A and 11B.

FIG. 11A is a perspective view illustrating the first inner rail 10A andthe first outer rail 20A of the slide rail assembly 1 according to asecond illustrative embodiment. FIG. 11B is a perspective viewillustrating the second inner rail 10B and the second outer rail 20B ofthe slide rail assembly 1 according to the second illustrativeembodiment. It is to be noted that, a description of those componentsexplained above in the first illustrative embodiment is omitted, and thesame reference numerals as those used in the first illustrativeembodiment are also used in the second illustrative embodiment. In theslide rail assembly 1 according to the second illustrative embodiment,the first inner rail 10A of the inner rail unit 10 further includes afirst stopper 17, the first outer rail 20A further includes a firststopper receiver 18 that contacts the first stopper 17 of the firstinner rail 10A, the second inner rail 10B of the inner rail unit 10further includes a second stopper 27, and the second outer rail 20Bfurther includes a second stopper receiver 28 that contacts the secondstopper 27 of the second inner rail 10B.

As illustrated in FIG. 11A, the first stopper 17 is provided between thefirst extending portion 13A and the first bulge 13B of the firstsubstrate 13 in the longitudinal directions. A part of the firstsubstrate 13 is cut in and bent toward the first outer rail 20A to formthe first stopper 17. In other words, the first stopper 17 is providedbetween the first and third rollers 11 and 21 in the slide directions inthe slide rail assembly 1.

The first stopper receiver 18 is provided between the third mountinghole 20 a, to which the third roller 21 is rotatably mounted, and thethird bulge 23A of the third substrate 23 in the longitudinaldirections. A part of the third substrate 23 is cut in and bent towardthe first inner rail 10A to form the first stopper receiver 18. In otherwords, in the slide rail assembly 1, the first stopper receiver 18 isprovided downstream from the first stopper 17 in the accommodationdirection of the sheet tray 202.

As illustrated in FIG. 11B, the second stopper 27 is provided betweenthe second extending portion 15A and the second bulge 15B of the secondsubstrate 15 in the longitudinal directions. A part of the secondsubstrate 15 is cut in and bent toward the second outer rail 20B to formthe second stopper 27. In other words, the second stopper 27 is providedbetween the second and fourth rollers 12 and 22 in the slide directionsin the slide rail assembly 1.

The second stopper receiver 28 is provided between the fourth mountinghole 20 b, to which the fourth roller 22 is rotatably mounted, and thefourth bulge 25A of the fourth substrate 25 in the longitudinaldirections. A part of the fourth substrate 25 is cut in and bent towardthe second inner rail 10B to form the second stopper receiver 28. Inother words, in the slide rail assembly 1, the second stopper receiver28 is provided downstream from the second stopper 27 in the withdrawaldirection of the sheet tray 202.

Thus, in the second illustrative embodiment, a part of the firstsubstrate 13 is cut in and bent toward the first outer rail 20A to formthe first stopper 17, and a part of the third substrate 23 is cut in andbent toward the first inner rail 10A to form the first stopper receiver18. As a result, slippage of the first outer rail 20A from the innerrail unit 10 is prevented without increasing the number of components.In addition, a part of the second substrate 15 is cut in and bent towardthe second outer rail 20B to form the second stopper 27, and a part ofthe fourth substrate 25 is cut in and bent toward the second inner rail10B to form the second stopper receiver 28. As a result, slippage of thesecond outer rail 20B from the inner rail unit 10 is prevented withoutincreasing the number of components.

It is to be noted that, although being L-shaped in cross-section in theforegoing illustrative embodiments, alternatively, the pairs of first,second, third, and fourth bent portions 14, 16, 24, and 26 may be eitherV-shaped in cross-section as shown in FIG. 12 or C-shaped incross-section, respectively. The shapes of the pairs of first, second,third, and fourth bent portions 14, 16, 24, and 26 in cross-section arenot limited to the above-described examples as long as the first,second, third, and fourth rollers 11, 12, 21, and 22 slidably engagetherewithin, respectively.

Although the two separate first and second inner rails 10A and 10B arefixed together to be assembled into the inner rail unit 10 in theforegoing illustrative embodiments, alternatively, the first and secondinner rails 10A and 10B may be formed together as a single integratedmember by casting or the like.

In the foregoing illustrative embodiments, the first, second, third, andfourth rollers 11, 12, 21, and 22, are rotatably provided to the firstand second inner rails 10A and 10B and the first and second outer rails20A and 20B, respectively. However, the configuration is not limitedthereto. Alternatively, the first, second, third, and fourth rollers 11,12, 21, 22 may be provided unrotatably to the first and second innerrails 10A and 10B and the first and second outer rails 20A and 20B,respectively, or be not cylindrically shaped, as long as a portion inwhich each roller contacts the corresponding rail has a reducedfrictional coefficient.

Although having the same shape and structure in the foregoingillustrative embodiments, the first and second inner rails 10A and 10Bmay have a different shape and structure and the first and second outerrails 20A and 20B may have a different shape and structure, as long asthe first and second outer rails 20A and 20B are slidable against theinner rail unit 10, respectively. In addition, although having the sameshape and structure, the first, second, third, and fourth rollers 11,12, 21, and 22 may have different shapes and structures, respectively,as long as the first, second, third, and fourth rollers 11, 12, 21, and22 are slidable against the respective bent portions 14, 16, 24, and 26.

Elements and/or features of different illustrative embodiments may becombined with each other and/or substituted for each other within thescope of this disclosure and appended claims.

Illustrative embodiments being thus described, it will be apparent thatthe same may be varied in many ways. Such exemplary variations are notto be regarded as a departure from the scope of the present invention,and all such modifications as would be obvious to one skilled in the artare intended to be included within the scope of the following claims.

The number of constituent elements and their locations, shapes, and soforth are not limited to any of the structure for performing themethodology illustrated in the drawings.

What is claimed is:
 1. A slide rail assembly, comprising: an inner railunit comprising: a rectangular inner substrate assembly; a pair of firstbent portions provided to a first side of the inner substrate assemblyin thickness directions, one end of the pair of first bent portionsbeing continuous with both edges of the inner substrate assembly inwidth directions, and opposite ends of the pair of first bent portionsbeing bent toward each other; and a pair of second bent portionsprovided to a second side of the inner substrate assembly opposite thefirst side in the thickness directions, one end of the pair of secondbent portions being continuous with both edges of the inner substrateassembly in the width directions, and opposite ends of the pair ofsecond bent portions being bent toward each other; a pair of first andsecond outer rails to sandwich the inner rail unit, the first outer railcomprising: a rectangular first outer substrate; and a pair of thirdbent portions, one end of the pair of third bent portions beingcontinuous with both edges of the first outer substrate in widthdirections, and opposite ends of the pair of third bent portions beingbent toward each other, the second outer rail comprising: a rectangularsecond outer substrate; and a pair of fourth bent portions, one end ofthe pair of fourth bent portions being continuous with both edges of thesecond outer substrate in the width directions, and opposite ends of thepair of fourth bent portions being bent toward each other, the pair offirst and second outer rails being disposed with the pairs of third andfourth bent portions facing inward, and being slidable against the innerrail unit in both a withdrawal direction and an accommodation directionalong longitudinal directions of the inner substrate assembly; a firstroller mounted to a leading end of the inner rail unit in the withdrawaldirection to slidably contact inner surfaces of the pair of third bentportions; a second roller mounted to a leading end of the inner railunit in the accommodation direction to slidably contact inner surfacesof the pair of fourth bent portions; a third roller mounted to a leadingend of the first outer rail in the accommodation direction to slidablycontact inner surfaces of the pair of first bent portions; and a fourthroller mounted to a leading end of the second outer rail in thewithdrawal direction to slidably contact inner surfaces of the pair ofsecond bent portions.
 2. The slide rail assembly according to claim 1,wherein: the inner substrate assembly is constructed of a first innersubstrate and a second inner substrate laminated together; the pair offirst bent portions is provided to the first side of the inner substrateassembly in the thickness directions with the one end thereof continuouswith both edges of the first inner substrate in width directions, andthe opposite ends thereof bent toward each other; and the pair of secondbent portions is provided to the second side of the inner substrateassembly in the thickness directions with the one end thereof continuouswith both edges of the second inner substrate in width directions, andthe opposite ends thereof bent toward each other.
 3. The slide railassembly according to claim 2, wherein the first roller and the secondroller comprise: a body having a hole at the center thereof; and a shaftinserted into the hole communicating with a through-hole penetratingboth the first and second inner substrates to mount the roller to theinner rail unit.
 4. The slide rail assembly according to claim 1,further comprising: a first stopper formed by a part of the innersubstrate assembly cut in and bent toward the first outer rail anddisposed between the first and third rollers in slide directions of thepair of first and second outer rails against the inner rail unit; and afirst stopper receiver to contact the first stopper, the first stopperreceiver being formed by a part of the first outer rail cut in and benttoward the inner substrate assembly and disposed downstream from thefirst stopper in the accommodation direction.
 5. The slide rail assemblyaccording to claim 4, further comprising: a second stopper formed by apart of the inner substrate assembly cut in and bent toward the secondouter rail and disposed between the second and fourth rollers in theslide directions; and a second stopper receiver to contact the secondstopper, the second stopper receiver being formed by a part of thesecond outer rail cut in and bent toward the inner substrate assemblyand disposed downstream from the second stopper in the withdrawaldirection.
 6. A sheet feeder, comprising: a sheet tray withdrawable fromthe sheet feeder to accommodate sheets; and a pair of slide railassemblies mounted to both lateral sides of the sheet tray to guide thesheet tray in a withdrawal direction, each of the pair of slide railassemblies comprising: an inner rail unit comprising: a rectangularinner substrate assembly; a pair of first bent portions provided to afirst side of the inner substrate assembly in thickness directions, oneend of the pair of first bent portions being continuous with both edgesof the inner substrate assembly in width directions, and opposite endsof the pair of first bent portions being bent toward each other; and apair of second bent portions provided to a second side of the innersubstrate assembly opposite the first side in the thickness directions,one end of the pair of second bent portions being continuous with bothedges of the inner substrate assembly in the width directions, andopposite ends of the pair of second bent portions being bent toward eachother; a pair of first and second outer rails to sandwich the inner railunit, the first outer rail comprising: a rectangular first outersubstrate; and a pair of third bent portions, one end of the pair ofthird bent portions being continuous with both edges of the first outersubstrate in width directions, and opposite ends of the pair of thirdbent portions being bent toward each other, the second outer railcomprising: a rectangular second outer substrate; and a pair of fourthbent portions, one end of the pair of fourth bent portions beingcontinuous with both edges of the second outer substrate in the widthdirections, and opposite ends of the pair of fourth bent portions beingbent toward each other, the pair of first and second outer rails beingdisposed with the pairs of third and fourth bent portions facing inward,and being slidable against the inner rail unit in both the withdrawaldirection and an accommodation direction along longitudinal directionsof the inner substrate assembly; a first roller mounted to a leading endof the inner rail unit in the withdrawal direction to slidably contactinner surfaces of the pair of third bent portions; a second rollermounted to a leading end of the inner rail unit in the accommodationdirection to slidably contact inner surfaces of the pair of fourth bentportions; a third roller mounted to a leading end of the first outerrail in the accommodation direction to slidably contact inner surfacesof the pair of first bent portions; and a fourth roller mounted to aleading end of the second outer rail in the withdrawal direction toslidably contact inner surfaces of the pair of second bent portions. 7.An image forming apparatus, comprising: a sheet feeder comprising asheet tray withdrawable from the sheet feeder to accommodate sheets; anda pair of slide rail assemblies mounted to both lateral sides of thesheet tray to guide the sheet tray in a withdrawal direction, each ofthe pair of slide rail assemblies comprising: an inner rail unitcomprising: a rectangular inner substrate assembly; a pair of first bentportions provided to a first side of the inner substrate assembly inthickness directions, one end of the pair of first bent portions beingcontinuous with both edges of the inner substrate assembly in widthdirections, and opposite ends of the pair of first bent portions beingbent toward each other; and a pair of second bent portions provided to asecond side of the inner substrate assembly opposite the first side inthe thickness directions, one end of the pair of second bent portionsbeing continuous with both edges of the inner substrate assembly in thewidth directions, and opposite ends of the pair of second bent portionsbeing bent toward each other; a pair of first and second outer rails tosandwich the inner rail unit, the first outer rail comprising: arectangular first outer substrate; and a pair of third bent portions,one end of the pair of third bent portions being continuous with bothedges of the first outer substrate in width directions, and oppositeends of the pair of third bent portions being bent toward each other,the second outer rail comprising: a rectangular second outer substrate;and a pair of fourth bent portions, one end of the pair of fourth bentportions being continuous with both edges of the second outer substratein the width directions, and opposite ends of the pair of fourth bentportions being bent toward each other, the pair of first and secondouter rails being disposed with the pairs of third and fourth bentportions facing inward, and being slidable against the inner rail unitin both the withdrawal direction and an accommodation direction alonglongitudinal directions of the inner substrate assembly; a first rollermounted to a leading end of the inner rail unit in the withdrawaldirection to slidably contact inner surfaces of the pair of third bentportions; a second roller mounted to a leading end of the inner railunit in the accommodation direction to slidably contact inner surfacesof the pair of fourth bent portions; a third roller mounted to a leadingend of the first outer rail in the accommodation direction to slidablycontact inner surfaces of the pair of first bent portions; and a fourthroller mounted to a leading end of the second outer rail in thewithdrawal direction to slidably contact inner surfaces of the pair ofsecond bent portions.